As a high-performance permanent magnet, rare-earth magnets such as an Sm—Co based magnet and an Nd—Fe—B based magnet are known. When a permanent magnet is used in a motor for a hybrid electric vehicle (HEV), electric vehicle (EV), railway vehicle, and so on, it is demanded for the permanent magnet to have heat resistance. In motors for HEV, EV, railway vehicle, and so on, the permanent magnet whose heat resistance is increased by replacing a part of Nd (neodymium) of the Nd—Fe—B based magnet with Dy (dysprosium) is used. Dy is one of rare elements, and thus a permanent magnet not using Dy is demanded.
The Sm—Co based magnet has a high Curie temperature and thus is known to exert excellent heat resistance as a composition system not using Dy, and is expected to achieve favorable operating characteristics at a high temperature. The Sm—Co based magnet is low in magnetization compared to the Nd—Fe—B based magnet, and is not able to achieve a sufficient value of maximum magnetization energy product ((BH)max). In order to increase magnetization of the Sm—Co based magnet, it is effective to replace a part of Co with Fe, and increase Fe concentration. However, coercive force of the Sm—Co based magnet tends to decrease in a composition region with high Fe concentration. Accordingly, there is demanded a technology to enable exertion of large coercive force while keeping high magnetization in the Sm—Co based magnet having a composition with high Fe concentration.